The present disclosure relates to a terminal including a high frequency (HF) transmission line using a printed circuit board.
Internal circuits of wireless communication devices are generally provided on printed circuit boards (PCBs). Such PCB technologies have been rapidly developed. Currently, there are generally used not only typical hard PCBs but also flexible PCBs (FPCBs) freely movable.
On the other hand, a coaxial cable is generally used as a high frequency (HF) line used in wireless terminals such as mobile phones, particularly, a radio frequency (RF) line. However, since an internal space of a wireless terminal is small and various kinds of circuit modules are mounted thereon, it is not easy to form a communication line using the coaxial cable in such space.
Accordingly, it is necessary to provide a transmission line capable of effectively transmitting an HF signal without noise while doing no harm on other modules. With respect to this, a structure, in which a signal is transmitted inside a wireless terminal using an FPCB, has been provided.
However, it is necessary to transmit an HF signal by using an FPCB between two parts mutually differing in height according to an arrangement of circuit modules in a wireless terminal. In this case, a separation distance occurs according to height and an uneven portion is formed when coupling with each other, thereby having a bad influence on signal transmission properties. When having a single layer, an FPCB has flexibility. However, since a height is formed by a thickness when an FPCB has a lamination structure, the FPCB is less flexible than the FPCB having the single layer and an arrangement thereof is not easy.
Also, when forming an HF transmission line and a data transmission line separately, space availability in a limited space of a mobile communication device in sync with miniaturization decreases and manufacturing costs increase according thereto.